Apparatus for making metal powder

ABSTRACT

A fluid nozzle structure is provided in an apparatus for atomizing molten metal of the type in which the molten metal to be atomized is fed as a hollow stream. The fluid nozzle structure comprises plenum-forming sections threaded in spaced relation on a feed pipe coaxial with the hollow metal stream. The plenumforming sections form a continuous radially outward presented fluid nozzle through which the atomizing fluid is directed. One of the plenum-forming sections is readily adjusted relative to the other to vary the size of the fluid nozzle.

United States Patent 1 Lafferty 1 Aug. 26, 1975 APPARATUS FOR MAKING METAL POWDER [75] lnventor:

[73] Assignee: Carpenter Technology Corporation,

Reading, Pa.

[22] Filed: Apr. 29, 1974 [21] Appl. No.: 464,948

James H. Lafferty, Reading, Pa.

[52] US. Cl 266/34 R; 75/59; 425/7 [51] Int. Cl. C2lC 7/00 [58] Field of Search 266/34 R, 35; 264/12;

[56] References Cited UNITED STATES PATENTS Earnshaw 266/34 R Scaright 425/7 X Primary ExaminerRoy Lake Assistant Examiner-Paul A. Bell Attorney, Agent, or FirmEdgar N. Jay

[ 57 ABSTRACT A fluid nozzle structure is provided in an apparatus for atomizing molten metal of the type in which the molten metal to be atomized is fed as a hollow stream. The fluid nozzle structure comprises plenum-forming sections threaded in spaced relation on a feed pipe coaxial with the hollow metal stream. The plenumforming sections form a continuous radially outward presented fluid nozzle through which the atomizing fluid is directed. One of the plenum-forming sections is readily adjusted relative to the other to vary the size of the fluid nozzle.

8 Claims, 1 Drawing Figure BACKGROUND OF THE INVENTION This invention relates to-new and useful improve ments in apparatus for atomizing a stream of molten metal into solidified particulates and, more particularly, to an improved nozzle structure for use with the apparatus disclosed in copending application Ser. No. 369,553, now U.S. Pat. No. 3,8l7,503 granted June 18, 1974. I

Said application Ser. No. 369,553 discloses an atomizing apparatus for use with a tundish or other container of a supply of molten metal which forms the molten metal into a hollow stream which surrounds a fluid nozzle assembly. Fluid jets from the nozzle assembly are directed radially outward from within the hollow stream and, on impingement with the stream, atomize it into particulates which fall radially outwardly away from each other and from the nozzle assembly.

Such nozzle assemblies as well as others leave much to be desired because they do not lend themselves to ready variation'or manipulation of the fluid jet or jets relative to the stream of molten metal to be atomized thereby.

SUMMARY OF THE INVENTION It is, therefore, a principal object of this invention to provide an improved nozzle assembly for atomizing molten metal to form metal powder.

Another object is to provide such an atomizing nozzle assembly which can be readily adjusted to vary the fluid jet.

The foregoing and other objects and advantages are achieved by providing a nozzle assembly comprising mating sections supported in opposed relation to form a plenum between them which provides free communication between a source of atomizing fluid under pressure on the one hand, and, on the other, with an annular fluid nozzle formed between close spaced portions of the opposed sections.

Readily adjustable support means are provided to hold one of the plenum-forming sections a predetermined distance from the other section. Preferably, the plenum-forming sections are supported on a pipe which distributes the atomization fluid to the nozzle assembly, and in the arrangement most preferred, the plenumforming sections are threaded on the feed pipe in spaced relation to form the plenum between them which communicates with the interior of the feed pipe through holes formed therein.

DESCRIPTION OF THE DRAWING Further objects and advantages of the present invention will be apparent from the following detailed descriptions and the accompanying drawing which is a somewhat schematic vertical section, partly in elevation, of an atomizing structure incorporating the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will now be described in detail in connection with a preferred embodiment thereof as used with an inert gas as the atomizing fluid.

Referring to the drawing in detail, the invention, as illustrated, is embodied in a nozzle assembly 7 shown for illustrative purposes in association with a tundish generally illustrated at 5, and a ceramic frusto-conical distributing element 6, as described in said application Ser. No. 369,553 which is incorporated here by reference to avoid unnecessary repetition. The bottom end of the distributing element 6 is recessed to receive and locate the atomizing fluid nozzle assembly 7 on which the former is supported. The atomizing fluid nozzle assembly 7 is in turn supported by the feed pipe 17 which thereby supports the entire atomizing assembly.

The atomizing fluid nozzle assembly comprises two sections, a lower section or body 20 and an upper section or cap 30, and a distributing support pipe 40.

The body 20 comprises a base 22 and an upstanding cylindrical wall 21, the former being threaded onto the gas feed pipe 17.

The cap 30 comprises a top stud or plug 31, a frustoconical intermediate portion 32, and an inclined lower portion 33. The cap 30 has a threaded recess 34 to receive the upper threaded end 41 of distributing pipe 40 which can be an integral extension of pipe 17 or, as shown, is welded to pipe 17. A lock screw 35 which functions as a stop is provided in the cap 30 and engages the closed end 41 of the pipe 40 and thus acts as an adjustment device for fixing the cap at a desired position on pipe 40 relative to the lower section or body 20. The inclined lower portion 33 is thus maintained a predetermined distance from the upwardly presented outwardly and downwardly inclined surface of wall 21 to form an annular slit or nozzle 15. Thus, by varying the depth to which the lock screw 35 allows the pipe end 41 into the recess 34, the distance across the slit 15 can be precisely adjusted.

Intermediate its ends, the distributing pipe 40 has three elongated holes 43 formed therein separated by three narrow support spiders 44. Although thus shown,

it will be readily apparent that a larger number of holes arranged in many possible configurations in the middle of the pipe 40 could be used. The only restrictions are that the holes be distributed about the pipe to give uniform jet velocity throughout the entire 360 extent of the slit l5, and that enough solid pipe is left to support the cap 30 and the molten metal distributing element 6. The array of three elongated holes 43 is believed to be the best arrangement for maximum and uniform atomizing fluid flow with adequate support for the upper sections. The interior of distributing pipe 40 communicates with the slit 15 through its holes 43 and a plenum 50 formed between the cap 30 and the body 20. Any undesired turbulence in the fluid flow that may be caused by the support spiders is substantially entirely dissipated in the plenum 50 and in passing through slit 15 so that the jet flow is generally laminar. Thus, a feature of this preferred embodiment resides in the arrangement of the support structure for the cap 30 which forms the upper side of the slit 15, so that the support structure is at substantially maximum spacing from the slit 15.

The angle of the slit or fluid nozzle 15 is not critical, but preferably it is such that it converges with the plane of the outer surface of the distributing element 6.

As described in said application Ser. No. 369,553, the distributing element 6 is supported in operative relation to the tundish 5 on the fluid nozzle assembly 7 which is in turn supported on the feed pipe 17. The feed pipe 17, in operation is connected to the source of atomizing fluid which can be a liquid such as water or a gas, preferably an inert gas such as argon under a pressure of at least about 300 psi to ensure desired atomization of the metal. Further operation of the atomizing apparatus of this invention will be apparent to those skilled in the art from the foregoing and from said application Ser. No. 369,553.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

1. In an apparatus for making metal powder by atomizing molten metal for use with a container for molten metal having a downwardly opening aperture in which a distributing element for the molten metal is supported by atomizing fluid nozzle and support means so that the upper portion of the distributing element forms an orifice with the wall of said aperture for the flow of molten metal therethrough downwardly about the outwardly presented periphery thereof, the improvement in which said atomizing fluid nozzle and support means comprises an atomizing fluid feed pipe having a plurality of openings formed adjacent to one end therof, an atomizing fluid nozzleand plenum-forming assembly including a body member and a cap member supported in mutually spaced relation on said feed pipe on opposite sides of said feed pipe openings, and said nozzleand plenum-forming assembly being supported within the periphery of and below said distributing element with the closely spaced opposed peripheral portions of said cap and body members forming an endless annularly extending atomizing fluid nozzle slit communicating with said feed pipe openings through a plenum formed between said cap and body members.

2. An apparatus as set forth in claim 1 which further comprises means for adjusting the distance between said cap and body members and thereby the distance across the nozzle slit between the peripheral portions of said cap and body members.

3. An apparatus as set forth in claim 2 in which said adjusting means extends between one of the nozzleand plenum-forming assembly members and said feed pipe.

4. The apparatus as set forth in claim 3 in which said means for adjusting the distance between said cap and body members extends between said cap member and feed pipe.

5. The apparatus as set forth in claim 3 in which said means for adjusting the distance between said cap and body members extends between said cap member and said one end of said feed pipe.

6. The apparatus as set forth in claim 5 in which said cap member is threaded on said feed pipe between said one end thereof and said openings, and said adjusting means comprises a member in threaded engagement with said cap member and forming a stop against said end of said feed pipe.

7. The apparatus as set forth in claim 6 in which said cap member has a threaded opening formed therethrough aligned with said feed pipe, and said adjusting means member extends in said threaded opening.

8. An apparatus as set forth in claim 7 in which said body member is threaded on said feed pipe. 

1. In an apparatus for making metal powder by atomizing molten metal for use with a container for molten metal having a downwardly opening aperture in which a distributing element for the molten metal is supported by atomizing fluid nozzle and support means so that the upper portion of the distributing element forms an orifice with the wall of said aperture for the flow of molten metal therethrough downwardly about the outwardly presented periphery thereof, the improvement in which said atomizing fluid nozzle and support means comprises an atomizing fluid feed pipe having a plurality of openings formed adjacent to one end therof, an atomizing fluid nozzle- and plenum-forming assembly including a body member and a cap member supported in mutually spaced relation on said feed pipe on opposite sides of said feed pipe openings, and said nozzle- and plenum-forming assembly being supported within the periphery of and below said distributing element with the closely spaced opposed peripheral portions of said cap and body members forming an endless annularly extending atomizing fluid nozzle slit communicating with said feed pipe openings through a plenum formed between said cap and body members.
 2. An apparatus as set forth in claim 1 which further comprises means for adjusting the distance between said cap and body members and thereby the distance across the nozzle slit between the peripheral portions of said cap and body members.
 3. An apparatus as set forth in claim 2 in which said adjusting means extends between one of the nozzle- and plenum-forming assembly members and said feed pipe.
 4. The apparatus as set forth in claim 3 in which said means for adjusting the distance between said cap and body members extends between said cap member and feed pipe.
 5. The apparatus as set forth in claim 3 in which said means for adjusting the distance between said cap and body members extends between said cap member and said one end of said feed pipe.
 6. The apparatus as set forth in claim 5 in which said cap member is threaded on said feed pipe between said one end thereof and said openings, and said adjusting means comprises a member in threaded engagement with said cap member and forming a stop against said end of said feed pipe.
 7. The apparatus as set forth in claim 6 in which said cap member has a threaded opening formed therethrough aligned with said feed pipe, and said adjusting means member extends in said threaded opening.
 8. An apparatus as set forth in claim 7 in which said body member is threaded on said feed pipe. 